This invention provides a method for centrifugally separating residual oil or other liquid waste contamination from granulated containers used to package the oil or liquid. In principle, the apparatus described herein consists of a horizontal centrifugal device which separates the oil from the container material in a continuous process. The centrifuge comprises a material auger contained within a perforated cylinder; the auger and perforated cylinder rotate as an assembly at sufficiently high angular velocity that the radial force acting against the liquid contaminant causes the liquid contaminant to flow from the granulated material. The separated liquid is slung into a liquid waste containment housing, while the granulated container material is continuously discharged from the auger.
With an understanding of the present need to protect both the natural environment and to optimize the use of natural resources, the importance of this apparatus and the ensuing method should be readily apparent. In a first case, a mechanical separation of the residual liquid (most notably, motor oil) from its granulated container assures fewer pollutants introduced into the waste water stream in the form of water and oil emulsions. In a second case, a mechanical separation assures a greater return of product into its highest value usage with the least energy expended; that is, motor oil may be recovered in the form of pure motor oil rather than as an emulsion which requires expensive reprocessing for commercial reuse.